Model 7158 Low Current Scanner Card Instruction Manual
Contents
1. ANALOG ANALOG INPUT nm sj OUTPUT CH1 0 CHS CHB 5 CH6 CHS CH4 CHS CH2 Vv DA VY NM YY LIT HD LIT D WD D 141 1 Li MAJA Dis M js MAI Do Tni e e e e e LA e LA e k k l k e e ae pee gS ALI e 4 1 4 z J 4i 3 a 3 4 5 t 4i 2 4 5 4 4 z 5 4 Na NY MT ae ny SA eget rh St E Vy 57 ODE 7 M 1 2 7 1 2 V 1 2 b 1 2 1 2 E 1 2 1 2 b 1 2 9 1 2 1 2 V PADD PADD FT AAAS CAAA K1 Ke 1 KS K4 KS di KO E K 1 K8 K K10 0 0 VM Di D WV 0 0 W 7 D 9 Y 7 Y ys 6 6 t 6 6 EN 6U 6U Cy C Gy 60 Ce S 4 Ir Y SC 201917 201 3 1 201291 2019 U1 2019 U 2019 1 22. 2 2 Installing Card in Model 705 2 3 Installing Card in Model 706 2 4 Model 7158 Simplified Schematic 2 5 Capacitor Leakage Schematic 2 6 Capacitor Leakage Instrument Setup 2 7 Measuring Leakages with One Card SECTION 3 SERVICING INFORMATION 3 1 Offset Current 000 cece e hes 3 2 Coax Pigtail Preparation 3 3 Contact Resistance D SECTION 4 REPLACEABLE PARTS 4 1 Model 7158 Component Layout 4 2 Model 7158 Schematic Diagram vivi SECTION 1 GENERAL INFORMATION 1 1 INTRODUCTION The Model 7158 Low Current Scanner Card has ten channels of paired single pole single throw SPST normally open NO relays The card will switch any one of ten signals to one output or switch one signal to any one of ten outputs signal HI is connected to signal LO analog ground when the scanner mainframe channel is open and to output HI when the channel is clos ed Signal LO is common to all ten channels and the output An addi tional relay isolates all circuitry on the card from the output when no channel is closed Features of the scanner card include e Low offset current error 1pA specified gt 3014 typical
3. Switching of AC or DC signals up to 100mA e BNC input and output connectors Two outputs for daisy chaining of Model 7158 cards Configurable for low current or low voltage switching The Model 7158 is field installable in the Models 705 and 706 scanner mainframes 1 2 WARRANTY INFORMATION Warranty information is stated on the inside front cover of this manual If there is a need for service contact the Keithley representative or authorized repair facility in your area Check the back cover for ad dresses The service form supplied at the end of the manual should be used to provide the service facility with information concerning any difficulty 1 3 MANUAL ADDENDA Product improvements or changes to this manual will be explained on an addendum included with the manual t is recommended that this information be incorporated immediatelv into the appropriate places in the manual If an additional instruction manual is required order the manual package Keithley Part Number 7158 901 00 The manual package in cludes an instruction manual and all pertinent addenda 1 4 SAFETY SYMBOLS AND TERMS The symbol A on the card denotes that the user should refer to the operating instructions The WARNING used in this manual explains dangers that could result in personal injury or death The CAUTION used in this manual explains hazards that could damage the card 1 5 UNPACKING AND INSPECTION The Model 7158 was inspected b
4. adil GN The Model 7158 can be mixed with cards other than 10 channel cards but there are complications when changing the pole mode to support a mix of card types When using a Model 7158 in combination with a 20 channel card such as the Model 7064 set the scanner to 1 pole mode In this mode each scanner channel controls one channel on one 20 channel card The effect on the Model 7158 channel assignments is shown in Table 2 2 NOTE In the 1 pole scanner mode close one channel at a time when using the Model 7158 Otherwise other channels are closed on the card and show up on the mainframe display For example close channels 2 and 5 channels 1 and 6 also close Table 2 2 Example Channel Assignments in 1 Pole Mode Card 1 Model 7158 Card 2 Model 7064 10 channels 20 channels Scanner 7158 Scanner 7064 Ch No Ch No Ch No Ch No SS 2 sl sl LU N A OS lt FO 53 Be Xd Un Next consider a mix of a 10 channel card Wo 7158 a 20 channel card Model 7064 and a matrix card Model 7052 in a Model 706 scan ner mainframe Since a matrix card is present the scanner is set to matrix 0 pole mode The scanner crosspoints and card channel assignments for a master scanner are shown in Table 2 3 Table 2 3 Example Channel Assignments in Matri
5. WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES NEITHER KEITHLEY INSTRUMENTS INC NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT INDI RECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS INC HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES SUCH EXCLUDED DAMAGES SHALL INCLUDE BUT ARE NOT LIMITED TO COSTS OF REMOVAL AND INSTALLATION LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON OR DAMAGE TO PROPERTY KEI THLEY Keithley Instruments Inc 28775 Aurora Road Cleveland OH 44139 216 248 0400 Fax 216 248 6168 e http www keithley com CHINA Keithley Instruments Chinas Yuan Chen Xin Building Room 705 No 12 Yumin Road Dewai Madian Beijing China 100029 8610 2022836 Fax 8610 2022 FRANCE Keithley Instruments SARL BP 60 3 all e des Garay 91122 Palaiseau C dex 31 6 0115135 Fax 31 6 0117726 GERMANY Keithley nsteumenis GmbH Landsberger Stafe 6 42 10 Germering 49 89 849307 0 Fax 49 89 84930759 GREAT BRITAIN Keithley Instruments Lid The Minster 58 Portman Road Reading Berkshite RG30 LEA 44 01734 575666 Pax 44 01734 596469 ITALY Keithley Instruments SRL Viele 5 Gimignana 38 20146 Milano 39 2 48303008 Fax 39 2 18302274 JAPAN Keithley KK Aibido Bldg e 7 20 2 Nishis
6. LE rA 3 4 LO NNN HI MODEL 5806 KELVIN TEST LEADS OHMS VOLTS Figure 3 3A Contact Resistance Signal HI to LO Relays 31 MODEL 7158 OUTPUT MODEL 5806 KELVIN TEST LEADS 196 DMM OHMS VOLTS Figure 3 3B Contact Resistance Signa HI to Output HI Relays 32 SECTION 4 REPLACEABLE PARTS 4 1 INTRODUCTION This section contains replacement parts information a component layout and a schematic diagram for the Model 7158 4 2 PARTS LISTS Electrical parts are listed in order of circuit designation in Table 4 1 Table 4 2 summarizes mechanical parts 4 3 ORDERING INFORMATION To place a parts order or to obtain information about replacement parts contact your Keithley representative or the factory See the back cover for addresses When ordering parts be sure to include the following information Scanner card model number 7158 Card serial number Part description Circuit description if applicable Keithley part number 33 Table 4 1 Model 7158 Electrical Parts Circuit Sch Keithley Desig Description Loc Part No C1 Capacitor 10 25V Aluminum C 314 10 Electrolytic C2 C5 Capacitor 0 111 50V Ceramic Film C 237 1 1 2 Connector Coaxial Female CS 249 K1 K21 Relay SPST NL70 R1 R10 Resistor 330111 5 4W Carbon R 76 330k Composition R11 Not used R12 R13 Resistor 10kQ 5 YW Carbon R 76
7. Remove the screws that secure the appropriate relay cover and remove the cover 2 Unsolder the defective relay and clean the card holes with a desolder ing tool or wick Solder in a replacement relay 3 Clean the card according to the method given in paragraph 3 2 us ing localized cleaning only then reinstall relay covers 26 3 4 RECOMMENDED TEST EQUIPMENT Table 3 1 lists recommended test equipment for performance verificz tion Other test equipment may be substituted if specifications equa or exceed those stated Table 3 1 Recommended Test Equipment Specification Description Scanner Mainframe Extender Card Low Noise Coax Cable Electrometer Triax to BNC Adapter Ohmmeter DMM Kelvin Test Leads 4 feet long 107 44 sensitivity 10 sensitivity 3 5 OFFSET CURRENT TEST This test verifies that the offset current for each channel is within specification 27 1 Set up the equipment as shown in Figure 3 1 with caps on all inputs and the unused output 2 Insert the card into the mainframe 3 Set the electrometer to the 2pA range and zero check 4 Turn on the mainframe and close channel 1 5 Zero correct the Model 617 and release its zero check Note the off set current long enough to allow the switching transients to decay and the current to stabilize The current indicated by the electrometer should be less than 1pA exclusive of noise Open the channel after taki
8. S 330K FOU 6U 6U 6U 6U 6 6U 6U 6 _ 0 0 0 0 0 0 0 0 3 6 21155 0 2 510 Dp 2 013 0 i E 8 lt R14 lt R14 R14 14 lt R14 lt R14 R14 lt R14 2 R12 R13 lt 10K S 10K lt 10K lt 10K S 10K lt 10K Sio S 10K RIP RUD 1 o8 de Js 94 95 11 9 L Lo Lo pe Ld i 22 25 23 21 19 11 13 2 9 3 P1 P1 P1 1 61 P1 P1 1 1 CH10 CH9 CHB CH7 CH6 CH5 CH4 CHS CH2 CH1 U2 2019 N 14 8 11 9 NC 14 NC 7 We x A M1 KEL HL KEITHLEY INSTRUMENTS INC Geh 00 MATES WITH 1012 OR J1013 SETTHLEY d H ES Ge E ER TITLE UNUSED GA ES ON AIN NAME 0 MODEL 205 1 ee e OR 7 e U2 2019 U2 5 LOW CURRENT SCANNER CARD 1e ur NC NC gt NC MATES WITH 1021 THRU 1 00 E 5 Lu cM 7404 f 5 1 7 pace MODEL N ECH REV ES 0 Hess TEE ON MAINFRAME OF MODEL 706 D D 2159 2158 106 11952 T D DRAWN APPROVED DATE 6U 0 CB DCL MS 3 10 87 8 7 6 5 4 5 KEIIHLEY Service Form Model No Serial No Date Name and Telephone No Company Lis
9. current and voltage to the card When fuses are used in a product replace with same type and rating for continued protection against fire hazard Chassis connections must only be used as shield connections for measur ing circuits NOT as safety earth ground connections If you are using a test fixture keep the lid closed while power is applied to the device under test Safe operation requires the use of a lid interlock If a Gi screw is present on the test fixture connect it to safety earth ground using 18 AWG or larger wire The symbol on an instrument or accessory indicates that 1000 or more may be present on the terminals Refer to the product manual for de tailed operating information Instrumentation and accessories should not be connected to humans Maintenance should be performed by qualified service personnel Before performing any maintenance disconnect the line cord and all test cables SPECIFICATIONS MODEL 7158 LOW CURRENT SCANNER CARD CHANNELS PER CARD 10 CONTACT CONFIGURATION Single pole When a channel is open signal HI is con nected to signal LO Signal LO is common for ali 10 channels and output CONNECTOR TYPE BNC RELAY DRIVE CURRENT 100mA per card typical MAXIMUM SIGNAL LEVEL 100mA 30V peak resistive load 3417 BANDWIDTH 1MHz typical CONTACT LIFE 107 closures cold switching 10 closures at maximum signal level CONTACT RESISTANCE lt 19 to rated life CONTACT POTENTIAL
10. present A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring Before operating an instrument make sure the line cord is connected toa properly grounded power receptacle Inspect the connecting cables test leads and jumpers for possible wear cracks or breaks before each use For maximum safety do not touch the product test cables or any other instruments while power is applied to the circuit under test ALWAYS re move power from the entire test system and discharge any capacitors be fore connecting or disconnecting cables or jumpers installing or removing switching cards or making internal changes such as installing or removing jumpers Do not touch any object that could provide a current path to the common side of the circuit under test or power line earth ground Always make measurements with dry hands while standing on a dry insulated surface capable of withstanding the voltage being measured Do not exceed the maximum signal levels of the instruments and acces sories as defined in the specifications and operating information and as shown on the instrument or test fixture rear panel or switching card Do not connect switching cards directly to unlimited power circuits They are intended to be used with impedance limited sources NEVER connect switching cards directly to AC main When connecting sources to switch ing cards install protective devices to limit fault
11. 019 U2 2 Nl ig 4 16 6 14 8 N 12 1 5 2 2 IN 18 aol 1 241 10 1 HC241 10 1 HC241 10 1 P241 10 1 HC241 10 1 HC241 1 1 HC24 9 Selz 5 d e d d d d 9 RS Y D y D D D 1 3 V 1 Y Y V V V TIE Ela S Teiz 1 1 g z 5 5 ls 5 ls gt z yl whee v v FRE v v BRE vl v RS v v PRSE v PRSE vy v vont v BRE v lt Ed 5 p V p 1 p S 5 5 5 5 j 5 2 AE 1 tom Sle a NL Ni 4 5 1 3K16 2 4K18 S 60 1 2 E 1 5 E E 7 L 5 y ke TA OPA ef beoe K N 2 1 i 4 1 4 4 1 4 1 4 1 4 1 4 1 4 1 4 1 4 1 4 e e e 0 4 e e ATE Tes W1 p 6 0 6 0 3 6 6U 6U 6U eu 6 H pu 6 T Y 144 14 U3 14 U3 14 U3 C4 14 3 cs 14 U3 14 4 e 1 lt e 3 o e 5 gt o 6 e 9 O 8 e 15 12 e 1 DS 2 21 e 9 2o 8 5 4HC04 4HC04 4HC0 4 744 4 4 E 4HC04 4HC04 7 6U 7 7 7 7 7 o Q L 7 V 9 V v V V pe gt SR Ra SRZ SR4 SRS SR SRE SRO SR SR10 16 330K 330K lt 330K gt 330K 330K lt 330K lt 330K gt 330K lt 330K
12. 10k Composition R14 Resistor Network 10k 2 1 5W TF 39 Thick Film TE3 TE4 Terminal Teflon TE 105 1 IC Buffer Line Driver and Receiver AHC241 IC Hex Inverter 4 IC 13 input NAND Gate 3 Cable Assembly Sockets 2 18 AWG Bare Buss Wire 22 AWG Bare Buss Wire 22 AWG Natural Thinwall Teflan Tubing These parts are static sensitive See paragraph 3 2 for handling precautions 34 Table 4 2 Model 7158 Mechanical Parts Keithley Description Part No 7158 303 Bracket Front Connector Mounting CH5 CH10 Bracket Rear Connector Mounting CH1 CH4 OUTPUT Cable Clamp Cover Front Relay CH5 CH10 Cover Rear Relay CH1 CH4 OUTPUT Protective Cap for BNC jacks 74 40 x 3 16 Phillips pan head sems screw for bracket mounting 76 32 x 1 4 Phillips pan head sems screw for cover mounting 7158 302 CC 38 4 7158 307 7158 304 CAP 18 4 4 FACTORY SERVICE If the scanner card is to be returned to Keithley Instruments for repair perform the following 1 Photocopy and complete the service form at the back of this manual and include it with the card 2 Carefully pack the card in the original packing carton 3 Write ATTENTION REPAIR DEPARTMENT on the shipping label Note that it is not necessary to return the scanner mainframe with the card 4 5 COMPONENT LAYOUT and SCHEMATIC DIAGRAM Figure 4 1 shows a component layout of the Model 7158 Figu
13. 2 6 27 2 42 2 7 28 2 43 2 8 29 2 44 2 9 30 2 45 2 10 17 2 5 2 Operation Notes 1 Extreme environmental conditions can cause the offset current to exceed the 1pA specification If the card has been exposed to high humidity and or temperature for example during shipping stabilize the board within the specified environmental limits for 24 hours 2 When a channel is opened or closed there is a charge transfer in the picocoulomb range This is because of the mechanical release or closure of the contacts the contact to coil capacitance and the stray capacitance between signai and relay drive lines The charge transfer causes a current pulse The effect on the signal depends on the magnitude of the source being measured 3 Each relay on the Model 7158 draws 10mA For current switching there are either ten or eleven relays energized with any combination of open and closed channels The maximum current draw of one card from the mainframe power supply is 110mA For voltage swit ching there are between zero and eleven relays energized for any open closed channel combination There are no restrictions on the maximum number of simultaneous channel closures unless relays from other card types are energized at the same time 4 System response is affected by cable capacitance This should be con sidered when the sources are connected to the scanner Use of a feed back ammeter or an electrometer in the FAST mode for currents b
14. 2004V ACTUATION TIME 1ms exclusive of mainframe OFFSET CURRENT 109A 3 x 10 typical COMMON MODE VOLTAGE 30V peak GENERAL ENVIRONMENT Operating 0 to 50 C up to 35 C at 70 RH Storage 25 to 65 C DIMENSIONS WEIGHT 32mm high x 114mm wide x 272mm long 1 3 x 455 x 10 Net weight 0 58kg 20 5 oz ACCESSORY SUPPLIED Model 4801 Low Noise Cable ACCESSORY AVAILABLE Model 4804 triax female to BNC male adapter Specifications subject to change without notice TABLE OF CONTENTS SECTION 1 GENERAL INFORMATION 1 1 Introduction 1 1 2 Warranty Information lese 1 3 Manual 43 1 4 Safety Symbols and Terms 1 5 Unpacking and Inspection 1 6 sj esi DM SECTION 2 OPERATION 2 1 Dee Te PPE E 22 Safety Precautions sirarsa 92 xac ade 2 2 1 High Impedance Considerations 2 2 2 Stalic l EGEaUDES com CESSES 2 Connecbons and Cabling ta decd param ba 24 Installation and Removal eei 27 ANE NEE 23 1 Scanner Control of the Channels 2 Operation Notes 2 6 yell ce seen atone SECTION 3 SERVICING INFORMATI
15. Model 7158 Low Current Scanner Card Instruction Manual Contains Operating and Servicing Information KEITHLEY WARRANTY Keithley Instruments Inc warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment Keithley Instruments Inc warrants the following items for 90 days from the date of shipment probes cables rechargeable batteries diskettes and documentation During the warranty period we wili at our option either repair or replace any product that proves to be defective To exercise this warranty write or call your local Keithley representative or contact Keithley headquarters in Cleveland Ohio You will be given prompt assistance and return instructions Send the product transportation prepaid to the indicated service facility Repairs will be made and the product returned transportation prepaid Repaired or replaced products are warranted for the balance of the origi na warranty period or at least 90 days LIMITAHON OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithley s express written consent or misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries damage from battery leakage or problems arising from normal wear or failure to follow instructions THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING ANY IMPLIED
16. ON 54 PAIIOGUCHON PR Handling and Cleaning 3 3 Relay Keplacemient 3 4 Recommended Test Equipment 3 5 Otiset Current Test 3 6 Contact Resistance Test EEN EEN EE SECTION 4 REPLACEABLE PARTS 4 1 Introduction O E E E 4 2 Parts 35 S 4 3 Ordering Information SEELEN NEEN EE E 4 4 Factory 610166 45 Component Layout and Schematic Diagram LIST OF TABLES SECTION 2 OPERATION 2 1 Example Channel Assignments in 2 Pole Mode 2 2 Example Channel Assignments in 1 Pole Mode 2 3 Example Channel Assignments in Matrix 0 Pole MOE e 2 4 Scanner Control of Model 7158 4 Pole Mode 2 5 Scanner Control of Model 7158 2 Pole Mode 2 6 Scanner Control of Model 7158 1 Pole Mode 27 Scanner Control of Model 7158 Matrix 0 Pole Mode SECTION 3 SERVICING INFORMATION 3 1 Recommended Test Equipment SECTION 4 REPLACEABLE PARTS 4 1 Model 7158 Electrical Parts 4 2 Model 7158 Mechanical Parts iii iv LIST OF ILLUSTRATIONS SECTION 2 OPERATION 2 1 Multi Card Connection
17. Pole Mode Card 4 Scanner Scanner Scanner Scanner Scanner 7158 Ch No Ch No Ch No Ch No Ch No Ch No GJ C Scanner Scanner Scanner Scanner Ch No Ch No Ch No Ch No Scanner Ch No 101 102 141 142 161 162 181 182 1 103 104 143 144 163 164 183 184 2 105 106 145 146 165 166 185 6 3 107 108 147 148 167 168 187 188 d 109 110 149 150 169 170 189 190 D 111 112 151 152 171 172 191 192 6 113 114 153 154 173 TA 193 194 7 115 116 155 156 175 176 195 196 8 117 118 157 158 177 178 197 198 9 119 120 159 160 179 180 199 200 10 16 Table 2 7 Scanner Control of Model 7158 Matrix 0 Poie Mode Scanner Scanner Scanner Scanner Scanner 7158 Ch No Ch No Ch No Ch No Ch No Owen ui U N e E Card 6 Card 7 Card 9 Card 10 Scanner Scanner Scanner Scanner Scanner 7158 Ch No Ch No Ch No Ch No Ch No Ch No 26 1 41 1 1 2 1 42 1 2 28 1 43 1 3 29 1 44 1 4 30 1 45 1 5 26 2 41
18. UTION Keithley s Model 7058 low current scanner card has triax connectors Be careful not to interchange triax and BNC connectors to avoid damaging them Caps are provided for all connectors Unused connectors should be cap ped to prevent contamination of the insulators which could degrade performance 6 The supplied low noise coax cable has a conductive lubricant graphite to minimize the error current caused by friction between cable insulators and conductors This becomes a consideration when measuring cur rent levels in the picoamp range Since cable flexing due to vibration and cable expansion and contraction due to temperature fluctuation cause friction the signal cables should be fastened to a rigid surface and not subject to temperature changes The temperature changes nor mally experienced in laboratory environments are not a problem MODEL 7158 MODEL 7158 INPUT OUTPUT INPUT OUTPUT Ae pl M o a SS lis CE MODEL 1 W LOW NOISE COAX PICOAMMETER Figure 2 1 Multi Card Connection 2 4 INSTALLATION AND REMOVAL The procedures to install the Model 7158 in the Model 705 or 706 Scan ners are similar except for the card orientation See Figure 2 2 for a Model 705 and Figure 2 3 for a Model 706 WARNING Turn off the scanner mainframe and disconnect the power cord before installing or removing scanner cards CAUTION Leave t
19. cted a current path is maintained through its signal HI to LO relay This protects sensitive devices under test from spikes when switching an ammeter in and out of each circuit The Model 7158 can also be configured for voltage switching schematic shown in Figure 2 4B This configuration is made possible by remov ing the socketed driver chips U1 and U2 for the channel HI to LO relay coils These chips are static sensitive See paragraph 3 2 for handl ing EE K21 Cri 1 ISOLATION CH 10 io A Current Switching Tdi K20 K21 9 ISOLATION LO HI HI CH 10 J10 OUTPUT LO LO B Voltage Switching Figure 2 4 Model 7158 Simplified Schematic 11 2 5 1 Scanner Control of the Channels Since the Model 7158 is a 10 channel card set the scanner to the 2 pole mode when using the Model 7158 by itself or when intermixing with other 10 channel cards such as Models 7056 7058 705 7066 and 7067 In the 2 pole mode each scanner channel controls one channel on one 10 channel card As an example consider the combination of a Model 7158 and Model 7059 Table 2 1 shows the scanner and card channel assignments for a master scanner Table 2 1 Example Channel Assignments in 2 Pole Mode Card 1 Model 7158 Card 2 Model 7059 10 channels 10 channels Scanner 7158 Scanner 7059 Ch No Ch No Ch No Ch No Co eons Gi va k CO
20. elow 10 is recommended to increase measurement speed and decrease the effects of cable capacitance 5 Power Limits To prevent overheating or damage to the relay con tacts never exceed the signal level specifications of the card Max imum switched and carry current and voltage levels are 100mA 30V The card can switch low power AC typical bandwidth up to 1MHz Maximum switched and carry current and voltage levels are 100mA 30V peak resistive loads 6 Switching Speed Relay actuation time is Imsec maximum plus the mainframe programming time Maximum relay switching rate is 100 cycles per second 10msec This is the maximum rate of the scan ner mainframe For extended relay life use low power or cold swit ching turn on sources after the channel is closed 2 6 APPLICATIONS The Model 7158 can be used in a variety of applications to switch low 18 current levels Typical applications include those where sourcing voltage and measuring current are required such as Leakage currents e g capacitor FET gate PCB test coupons Materials research and characterization e Semiconductor sub threshold current Voltage applications include those where the Model 7158 can be used to switch a single pole of low voltage sources Refer to the application example that follows When measuring low currents the following sources of noise current should be considered Triboelectric currents are caused by friction b
21. etween a conductor and insulator when a coax cabie flexes due to vibration or temperature fluctuation To minimize use low noise cables and tie down to a rigid surface Piezoelectric currents are caused by mechanical stress to the insulating materials of connectors Remove the stress from the insulators and use materia with low piezoelectric effects to minimize Electrochemical effects generate current between PCB conductors due to contamination of the card surface To minimize handle the card by the edges only and follow the cleaning instructions in paragraph 2 For a specific application consider measuring capacitor leakage cur rent to calculate insulation resistance The amount of leakage current depends on the capacitor dielectric material as well as the applied voltage The schematic of Figure 2 5 shows a Model 7055 7056 card on the source side but a Model 7158 could be used in its voltage configura tion when the test voltage does not exceed 30V The configuration shown is the direct method of measuring leakage currents a feedback type picoammeter in series with the capacitor under test This test is fully explained including controlling software 19 and test fixture construction in Application Note 120 Capacitor Leakage Measurements NOTE The indirect method with a voltmeter reading the voltage drop across a resistor in series with the capacitor is recommended for capacitor values above 1 F to maintain stab
22. he Model 617 has settled and the measurement is taken the Model 7158 channel is opened and the signal HI to LO relay closes to shunt the current to ground Then the Model 7056 channel is opened to avoid a current surge through the electrometer and resistors R1 and R2 bleed off the capacitor charge With this two card configuration the capacitors have equal soak times This is important when comparing low leakage levels picoamps Having equivalent soak times is not as critical at higher leakage levels e g the nanoamp range of tantalum capacitors n this case the one card configuration shown in Figure 27 is sufficient Since the settling time of the Model 617 is less when measuring higher currents the chan nels can be switched faster 22 M n MODEL 8 Figure 2 7 Measuring Leakages with One Card 23 24 SECTION 3 SERVICING INFORMATION 3 1 INTRODUCTION This section describes tests for verifying the performance of the Model 7158 Perform these tests in an environment of 18 C to 28 C up to 70 RH Because of the low signal levels measured in these tests the test cables should be kept as still as possible to help minimize noise Recommended maintenance includes inspection of the card and the card edge connector to ensure good electrical contact 3 2 HANDLING AND CLEANING Because of the high impedance of the board take special care when handling and using t
23. he Model 7158 in its anti static bag until ready for cabling and installing to avoid possible static damage Once the card is cabled insert it card edge first into the scanner main frame by aligning it with the grooves in the appropriate slot Make sure it is properly seated into the mainframe connector Push the locking tabs forward to the center of the card to lock it in To remove a card first turn off the mainframe and all other equipment connected to the card Unfasten the locking tabs on the card by pull ing the tabs outward Grasp the end of the card and carefully pull it out of the mainframe 7150 LOCKING TABS MODEL 705 REAR PANEL 1 OF 2 7158 CARD INSTALLED Figure 2 2 Installing Card in Model 705 MODEL 8 REAR PANEL 7158 CARDS Figure 2 3 Installing Card in Model 706 2 5 OPERATION As shown in Figure 2 4A for current switching each channel on the Model 7158 has a pair of single pole single throw SPST normally open NO relays The relay pair switches signal HI between signal LO analog ground and output HI Signal LO outside shell of the BNC is com mon to all channels and outputs in the system An additional relay isolates all circuitry on the card from the outputs when no channel is closed That is the isolation relay is open when all channels are open and it is closed when any channel is closed 10 The card is designed for scanning current sources when a channel is not sele
24. hecking Signal HI to LO Relays 5 Connect one of the BNC plugs to an input connector on the card Connect the Kelvin leads to the coax pigtail as shown in Figure 3 3A 6 a all channels open verify that the contact resistance is less than 6 7 Verify the resistance of the remaining signal HI to LO relays by just moving the BNC plug and Kelvin leads to the remaining input con nectors and taking readings 29 3 4 a Ea red iA CUT OFF INSULATION WITH X ACTO KNIFE Bj UNRAVEL AND TWIST SHIELD BRAID 8 ar 6 STRIP CENTER CONDUCTOR Figure 3 2 Coax Pigtail Preparation Checking Signal HI to Output HI Relays and Isolation Relay 8 Connect one of the BNC plugs to an input connector and the other BNC plug to an output connector Connect the Kelvin leads to the coax pigtails as shown in Figure 3 3B 9 Program the scanner to close the channel being tested This closes both the signal HI to output HI relay and the isolation relay for measuring 10 Verify that the contact resistance of the relay combination signal HI to LO relay and isolation relay is less than 12 Open the chan nel after taking the reading 30 11 Continue with the remaining channels by leaving one BNC plug on the output connector and moving the other BNC plug and Kelvin leads to the remaining input connectors Take readings with the ap propriate channel closed MODEL 7158 INPUT OUTPUT 1 BNC
25. hinjulu Shinjuku ku Tokyo 160 81 3 5389 1964 Fax 81 3 5389 2668 NETHERLANDS Keithley Instruments BV Avelingen West 49 e 4202 MS Gorinchem 31 0 183 635333 Fax 31 0 183 630821 SWITZERLAND Keithley Instruments SA Kriesbachstrasse 4 8600 D bendorf e 41 1 8219444 Pax 41 1 8203081 TAIWAN Keithley Insiruments Taiwan 1 Ming Yo First Street Hsinchu Taiwan ROC e 886 35 778462 Fax 266 35 5 Model 7158 Low Current Scanner Card Instruction Manual 1987 Keithley Instruments Inc Test Instrumentation Group All rights reserved Cleveland Ohio U S A June 1990 Second Printing Document Number 7158 901 01 Rev B SAFETY PRECAUTIONS The following safety precautions should be observed before using this product and any associated instrumentation Although some instruments and accessories would normally be used with non hazardous voltages there are situations where hazardous conditions may be present This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury Read the operating information carefully before us ing the product Exercise extreme caution when a shock hazard is present Lethal voltage may be present on cable connector jacks or test fixtures The American National Standards Institute ANSI states that a shock hazard exists when voltage levels greater than 30 RMS 42 4 peak or 60VDC are
26. ility and noise performance The instrument setup is shown in Figure 2 6 For clarity only four chan nels are shown Obviously all ten channels are available for testing purposes TO OTHER CHANNELS MODEL 7055 7056 _ 1 OTHER CAPACITORS 7 SHIELDED FIXTURE TOOTHER CHANNELS MODEL Figure 2 5 Capacitor Leakage Schematic 20 INPUT ANG MODEL 7 TRIAX TO ANC ADAPTER MODEL 7158 INPUT MOOEL 87 ENH 7 ELECTAOMETER V SGUIICE OUTPUT LO ni E gt Vi GUARO LT TT r 6 MODEL 1 LOW NOISE COAX cll VE RW ER SHIELDED TEST FIXTURE cita CH CHE CHS OUTPUT CH10 CH9 MODEL 7055 7056 Figure 2 6 Capacitor Leakage Instrument Setup The internal voltage source of a Model 617 electrometer stagger charges the capacitors when the corresponding channels are closed on a Model 7056 general purpose card At this time the signal HI to LO relay on 21 the Model 7158 is closed completing the circuit Resistor R1 is needed to limit current in case the capacitor ts shorted and it also helps reduce noise After each capacitor is fully charged usually 10 times RIC the Model 7158 channel is programmed to close This switches in the Model 617 for reading current or resistance V I mode Once t
27. its on the card be careful when handling it to avoid contamination from such foreign materials as body oils Such contamination can substantially lower leakage resistance degrading performance Handle the card only by the edges If you remove the relay covers be careful not to touch board surfaces or exposed parts To avoid dirt build up over a period of time operate the scanner and scanner card only in a clean environment If contamination is suspected the card should be carefully cleaned using the procedure given in paragraph 3 2 2 2 2 Static Precautions The card s IC chips are static sensitive and can be damaged by static discharge rendering the card partially or completely inoperative For that reason be careful not to touch exposed areas of the circuit board if static is thought to be a problem CAUTION Static discharge to exposed circuits can damage the card and might invalidate the warranty 2 3 CONNECTIONS AND CABLING Signal input and output connections are made with BNC connectors on the card The locations for each channel input and the outputs are indicated on the relay covers The two output connectors permit multi ple Model 7158 cards to be connected together For example a 20 channel scanner system can be connected as shown in Figure 2 1 In addition to card to card connections the Model 4801 low noise cable can be used for scanner to scanner connections when daisy chaining up to five scanner mainframes CA
28. ng the reading 6 Close the remaining channels one at a time and repeat step 5 MODEL 7158 OUTPUT MODEL 4801 LOW NOISE COAX MODEL 6147 TRIAX TO BNC ADAPTER MODEL 617 ELECTROMETER i GROUND INPUT LINK IN TRIAX VO GUARD OFF HJ Figure 3 1 Offset Current 28 3 6 CONTACT RESISTANCE TEST This test verifies that the contact resistance of the relays does not ex ceed the specification The procedure is in three parts Setting up equipment Checking contacts of signal HI to LO relays when channel is open Checking contacts of signal HI to output HI relays in combination with the isolation relay when channel is closed Setting Up Equipment 1 Turn on the Model 196 DMM and let it warm up two hours if from cold start 2 Using the following procedure two BNC male connectors with coax pigtails as shown in Figure 3 2 Use an X acto knife to cut and strip 1 inches of outer insula tion without cutting the shield With the knife point unravel the braided shield and twist it off to the side Strip one inch of insulation off the center conductor Connect the Model 7158 to the scanner through the Model 7061 Universal Adapter Card which is used as an extender to allow ac cess to all connectors Select the 3000 range on the Model 196 Temporarily short the test leads and zero the instrument Leave zero enabled for the duration of the test oJ C
29. o prevent degradation of performance Handle the board by the edges to avoid contaminating it with dirt body oil etc CMOS and other high impedance devices are subject to possible static discharge damage because of the high impedance levels involved When handling such devices indicated by in the parts list use the follow ing precautions 1 Such devices should be transported and handled only in containers specially designed to prevent or dissipate static build up Typically these devices will be received in anti static containers of plastic or foam Keep these parts in their original containers until ready for installation 2 Remove the devices from their protective containers only at a pp grounded work station Also ground yourself with a suitable wrist strap 25 3 Handle the devices only by the body do not touch the pins 4 Any printed circuit board into which the device is to be inserted must also be grounded to the bench or table 5 Use only anti static de soldering tools and grounded tip soldering irons Before cleaning the board remove the front and rear relay covers Clean the board with cotton swabs or a soft brush saturated with an uncon taminated solvent such as Freon TMS or TE After the solvent has been applied and is still liquid blow dry the board with dry pumped nitrogen gas 3 3 RELAY REPLACEMENT If you have determined that a relay is defective use the following pro cedure to replace it 1
30. oth electrically and mechanically before shipment Upon receiving the Model 7158 unpack all items from the SE carton and check for any obvious damage that may have oc curred during transit Report any damage to the shipping agent Re tain and use the original packaging materials in case reshipment is necessary The following items are shipped with every Model 7158 Model 7158 Low Current Scanner Card Model 7158 Instruction Manual Model 4801 Low Noise Coax Cable 48 in supplied accessory The following item is an optional accessory Model 4804 Triax F to BNC M Adapter 1 6 SPECIFICATIONS Detailed specifications of the Model 7158 precede the Table of Contents of this manual 3 4 SECTION 2 OPERATION 2 1 INTRODUCTION This section contains an operation overview safety information con nections and cabling information an installation procedure operating instructions and an application for the card 2 2 SAFETY PRECAUTIONS WARNING Maintain inputs and outputs within 30V peak of earth ground Turn off all power and discharge stored energy in external circuitry before making or breaking connections 1 The maximum signal level is 100mA peak 30V compliance 2 Make sure the scanner mainframes are grounded through an earth grounded receptacle before operation 3 Inspect all connections for wear and defects such as cracks and ex posed wires 2 2 1 High Impedance Considerations Because of the high impedance circu
31. re 4 2 shows a schematic diagram of the Model 7158 35 CJ 0 G o 11855 RELEASED ess ADDED DETAIL FOR TP 10 DELETED DETAIL B 1 B4 12511 ADDED 50 84 20 TO __ RELAY LEAD 6 20 TEFLON TUBING 2 2 OIN crue 302 BRACKET amp 4 40x2 16 PPHSEM US WIRE LON TUBING 7158 303 BRRCKE 4 40x3 16 PPHSEM 2 R 7 MC 285 18 BUS WIRE 58 070 CABLE ASS Y NOTE FOR COMPONENT INFORMATION REFER TO BILL OF MATERIAL 7158 000 00 Ex ca MOUNT C1 HORIZONTA TO PC BOARD 2258 fo MODE NEXT ASSEMBLY arv 8 5 SEA RZ USED ON een SBS DIMENSIONAL TOLERA 2 11 87 1 52 DO NO SCALE THIS DRAWING UNLESS OTHERWISE SPECIFIED DATE 2711787 COMPONENT AYOUT DRN MH ENG DC CURRENT SCANNER CARD KEITHLEY INSTRUMENTS INC los i pi 5 FRAC 1 64IMRTERTRL CLEVELAND OHIO 44139 SURFACE MAX D FINISH F N
32. t all control settings describe problem and check boxes that apply to problem C Intermittent Cl Analog output follows display Particular range or function bad specify IEEE failure Obvious problem on power up Batteries and fuses are OK 00 C Front pane operational An ranges or functions are bad Checked all cables Display or output check one C Unable to zero Wili not read applied input Unstable Overload Calibration only CJ Certificate of calibration required Data required attach any additional sheets as necessary Show a block diagram of your measurement system including all instruments connected whether power is turned on or nol Also describe signal saurce Where is the measurement being performed factory controlled laboratory out of doors etc una e M 1 What power line voltage is used Ambient temperature F Relative humidity Other Any additional information If special modifications have been made by the user please describe EE gp E Or a Keithley Instruments Inc Test Instrumentation Group 28775 Aurora Road Cleveland Ohio 44139 Printed in the U S A
33. x 0 Pole Mode Card 1 Model 7158 Card 2 Model 7064 Card 3 Model 7052 10 channels 20 channels 5 Columns by 4 rows 7052 706 706 7064 706 Column Crosspoint Ch No Crosspoints Ch No Crosspoint Row SOON DO WN 5 3 Ne When using 20 channel cards in matrix mode two crosspoints must be closed for each of the card channels general the rules for choosing different scanner pole modes are matrix 0 pole If a matrix card is present 1 pole If a 20 channel card is present but no matrix card 2 pole If a 10 channel card is present but no 20 channel or matrix cards 14 4 pole If 4 pole switching is desired with two 2 pole 10 channel cards Tables 2 4 through 2 7 list the scanner channels that control Model 7158 channels for all scanner pole configurations Table 2 4 Scanner Control of Model 7158 4 Pole Mode Channel No Channel No 705 706 705 706 706 706 706 706 706 706 706 706 Card No 3 Table 2 5 Scanner Contro of Mode 7158 2 Pole Mode Scanner 7158 Card No Channel No Channel No 01 10 1 10 705 706 11 20 1 10 705 706 21 30 1 10 706 31 40 1 10 706 41 50 1 10 706 51 60 1 10 706 61 70 110 706 71 80 1 10 706 81 90 1 10 706 91 100 1 10 706 U uh Coo 15 Table 2 6 Scanner Control of Model 7158 1
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